How about a Detachable Aircraft Cabin?

Last year I had to make 26 airflights in the space of 3 months to Pietermaritzburg. As this is a small airport, the planes are usually small & some even minute. Most flights do not experience too much turbulence but one of them was extremely bumpy the whole way, dropping by hundreds of metres as it hit an air pocket. I was happy to forego the inflight snacks but I had one hour to contemplate the what-ifs and attendant dangers of airflight.

Falling out of the sky may well be most passengers’ worst nightmare when they board a plane. Perhaps a detachable cabin is an elegant solution to this problem. It would certainly reassure many passengers that their chances of survival are enhanced over the crash-into-the-ground option currently in vogue. 

Main picture: Parachuting gently to earth instead of the crash-into-the-ground option currently in vogue

Air flight might be the safest form of transport, yet when something goes drastically wrong with a plane, the chances of survival of the resulting crash are miniscule. During WW1, the RAF even refused to supply their pilots with a parachute in case they took the easy way out, and instead of attempting to save their plane, they merely parachuted to safety.

If this pilot had been allowed to carry a parachute, he might have survived

If this pilot had been allowed to carry a parachute, he might have survived

One would hope that the safety of pilots and passengers is nowadays ranked as more important than such monetary considerations but sometimes I doubt that after watching certain documentaries on air crash investigations.

Essentially when an aircraft experiences difficulties, what options do the passengers have? They must trust the competence of the pilot to take the correct decision and if it is a crash landing, just hope that there is a suitable landing spot.

Perhaps this option is too extreme for Mrs Granny Smith but would most passengers not use the option if there were no other alternatives?

Perhaps this option is too extreme for Mrs Granny Smith but would most passengers not use the option if there were no other alternatives?

One possible solution would be to issue the passengers with parachutes – at a price no doubt. Other changes to the aircraft’s construction itself might be necessary such as a door over the wing. Perhaps an attachment at the door for one’s parachute cable in order to pull the parachute out as one slid off the wing. The safety instructions would then have to include a practical demonstration on how to operate the parachute.

There are three possible negative consequences of this suggestion apart from the cost, what about the space and weight considerations. All are critical in the design and economics of air flight. In addition as events have proved in the shipping industry, it has often been proved that the ship’s captain is the first to be rescued or to abandon ship. With his inside knowledge of the aircraft’s situation, wouldn’t the captain be tempted to be first out?

Pic shows: The Spanish army is introducing the world's first tandem flight for dog and handler. The Spanish army is taking the term dogs of war to a new height after introducing the world's first tandem flight for dog and handler. Until now army dog trainers have had to go through specialist parachute training in order to jump from planes with their canine partners. But the new system in Spain involves an experienced Parachute Regiment officer jumping with the army dog handler and the dog. And in trials like this one at a drop zone of Santorcaz, in the centre Spanish region of Madrid, it worked perfectly, with both dog and handler being safely delivered to the ground by the professional parachutist. In the first jump a dog specialised in sniffing out explosives was able to leap out of the plane with its owner and a soldier from the Parachute Regiment. In the second jump another dog called Jimy specialised in tracking and attacking on command was involved. Both were securely strapped to their handler and with a muzzle to stop them damaging their mouths on landing. Spanish army spokesman XXXX said: "both dogs were Belgian shepherds. The jump was made from a height of 10,000 feet and the tests proved that both dogs and handler can work properly after the freefall." The idea of parachuting dogs is not anything unusual as these snaps taken at a cross-border parachuting dog training session in Norway in which the Austrian army was involved. The pictures as the explosives sniffing pooch - a member of Austria's version of the SAS - were taken as the plane and its handler out of the plane part in Operation Cold Response. Although the Austrian dogs seemed very cool his handler explained: "They don't perceive height difference the same way humans do, so it doesn't worry them. They're more likely to be bothered by the roar of the engines, but once we're on the way down, that doesn't matter and they just enjoy the view." He was also eager to point out that the dogs, like their human colleagues, are regarded as valued team members and aren't put into situations that could prove unnecessarily dangerous. (ends)

How about a tandem jump if you are too scared?

With this mind, a Ukrainian inventor has proposed building airliners with detachable passenger cabins that could separate from the rest of the plane and parachute safely to the ground in the event of an emergency.

The idea is simplicity itself. The plane would be constructed with a detachable passenger compartment. In the event of an emergence – translated into South African as GROOT K*K – the detachable compartment would be released, floating safely to earth under gigantic parachutes. In order to make the landing even more comfortable, a large air bag would be inflated under the plane. What the designer fails to mention is that in reality the passengers would experience a huge jolt as the passenger compartment bounced off the ground. Instead in the designer’s mind, the passengers would then calmly finish their drinks and placidly step off the plane while the rest of the plane together with its flight crew crashed to their deaths with the remnants of the plane.

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Unfortunately Herve Morvan, Professor in Applied Fluid Mechanics and Director, Institute for Aerospace Technology, Faculty of Engineering, University of Nottingham has debunked this whole notion as at best facile and possibly totally impractical.

Maybe I should not have read his rebuttal but it is included verbatim below:

As someone with a keen interest in aircraft design and technologies, I found the plan a bemusing distraction. Not only would such a design be prohibitively expensive, it would also be unlikely to save any lives in all but a very few airline disasters.

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While the video proposal shows the detachable cabin deploying on a plane experiencing engine failure, it should first be noted that crashes due to this problem are exceptionally rare. Systems and power failures have accounted for less than 3% of all fatal accidents in the past 10 years. From the beginning the argument did not stack up.

An aircraft is most vulnerable during take-off and landing because it is closer to the ground (its biggest obstacle), and is travelling at low speeds and therefore is harder to manoeuvre. According to statistics from Boeing, almost three-quarters of deaths from plane crashes between 2005 and 2014 occurred during these phases of flight.

What are one's chances of surviving this crash

What are one’s chances of surviving this crash

But this is the time when a detachable cabin would least likely be successful at saving lives. Being closer to the ground would give the pilot much less opportunity to jettison the cabin following an incident and if it were detached it could well land in a built-up area.

Nevertheless, slightly over 1000 lives have been lost in the past ten years due to accidents during the cruise phase of flight, when a detachable cabin might have been of most value. But even during this stage of flight, it is difficult to see that the technology would often be effective. Most aircraft accidents – as many as 80% – are due to human error, with the most common being loss of aircraft control and flight into or towards terrain. A detachable cabin would probably be impossible to deploy safely if the pilot had lost control of the plane, or if it was about to fly into the terrain.

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Quick thinking

Even in cases where the pilot can respond calmly and quickly to something that wasn’t their fault, it is a struggle to see how a detachable cabin could usually play a significant role. Take US Airways flight 1549, which saw pilot Chesley B Sullenberger land the plane in the Hudson river in New York after birds flew into the engines at take-off.

Flight 1549 crash landed in the Hudson River

Flight 1549 crash landed in the Hudson River

 

Though manufacturers cannot prepare for every scenario, engines are tested for bird ingestion and designed to survive them, at least for a while. Aircraft can also continue to ascend with one engine down. In this case, however, the captain was particularly unlucky to lose all power and was therefore unable to fly back around for an emergency landing at an airfield. What would a detachable cabin have resolved there? At low altitude it is unlikely it could have been deployed in the first place. Then, what if the cabin had landed on the city?

Practically, there is also the technical complexity of actually building such a system, the mechanisms and bolts to secure the cabin but also allow its safe release in flight. You can add to this the service issues and maintenance challenges.

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In addition, there is the excess weight of the proposed system. Weight is everything for aircraft manufacturers. Every extra kilogram requires more thrust and a higher fuel burn.

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Despite these flaws, this actually is not the first time a detachable cabin system has been envisaged. Following the Challenger shuttle disaster in 1986, designers on the European Hermes space shuttle programme looked at the possibility but found it hugely expensive as well as impacting what the shuttle could carry. The system ended up being one of several fatal blows to Hermes and the shuttle was never built.

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Sources:

Internet: http://theconversation.com/why-a-detachable-cabin-probably-wont-save-your-life-in-a-plane-crash-53532

YouTube: https://www.youtube.com/watch?v=ZPkr3A9DTOc


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